1. Field of the Invention
The present invention relates to a light emitting type push button switch mounted on a control panel.
2. Description of Related Art
This kind of switch comprises an indication unit and a switch unit removably connected to each other. The indication unit has an operation block containing an indicator. The switch unit has a microswitch which is turned on or off by the pushing of the operation block through a plunger held to be longitudinally movable in the case of the indication unit.
Referring to FIG. 23, a known construction of the indication unit and the switch unit which are connected to each other is described hereinbelow. Switch unit 203 is shown with three rows of extending terminals 211 and 212 as output terminals of the switch unit. An approximately T-shaped engaging projection 202 is formed on the indication unit 201, and as shown in FIG. 24, a plurality of a pair of elastic arms 206 and 207 connected by a rectangular pressure applying plate 205 are formed on the front of a microswitch 204, and as shown in FIG. 25, a pair of engaging projections 208 and 209 which removably engage with both sides of the engaging projection 202 is formed on the inner wall of the pressure applying plate 205.
However, since the elastic arms 206 and 207 are disposed on the front of the microswitch 204 of the switch unit 203, the elastic arms 206 and 207 and the pressure applying plate 205 which are connected with the indication unit 201 are disposed between the indication unit 201 and the switch unit 203. Therefore, the switch is long lengthwise, i.e., it is difficult to manufacture a compact switch.
In particular, since this construction does not allow the formation of the long elastic arms 206 and 207, the flexible amount of the elastic arms 206 and 207 is small, and the switch unit 203 and the indication unit 201 cannot be easily engaged with each other or disengaged from each other by the pressure applying plate 205. Therefore, when a great force is applied to the button, the elastic arms 206 and 207 may be damaged.
Since the elastic arms 206 and 207 are formed on the pressure applying plate 205, the space of the pressure applying plate 205 is comparatively large. But, the provision of the small pressure applying plate 205 makes it difficult to engage the switch unit 203 and the indication unit 201 with each other or disengage them from each other.
If the external terminal of the microswitch 204 and the one for connecting the indicator to the switch unit are provided with screws, both external terminals are cylindrically formed and a male screw is screwed in a female screw formed on the end face of each of the cylindrical terminals. In this case, it is necessary for the switch case to have two configurations, which leads to the preparations of increased number of metal molds.